Remove unused allow declarations for removed methods

spec/features/expand_collapse_diffs_spec.rb

@@ -7,11 +7,6 @@
   let(:project) { create(:project, :repository) }
 
   before do
-    # Set the limits to those when these specs were written, to avoid having to
-    # update the test repo every time we change them.
-    allow(Gitlab::Git::Diff).to receive(:size_limit).and_return(100.kilobytes)
-    allow(Gitlab::Git::Diff).to receive(:collapse_limit).and_return(10.kilobytes)
-
     sign_in(create(:admin))
 
     # Ensure that undiffable.md is in .gitattributes

spec/features/merge_request/user_expands_diff_spec.rb

@@ -7,9 +7,6 @@
   let(:merge_request) { create(:merge_request, source_branch: 'expand-collapse-files', source_project: project, target_project: project) }
 
   before do
-    allow(Gitlab::Git::Diff).to receive(:size_limit).and_return(100.kilobytes)
-    allow(Gitlab::Git::Diff).to receive(:collapse_limit).and_return(10.kilobytes)
-
     visit(diffs_project_merge_request_path(project, merge_request))
 
     wait_for_requests

spec/features/merge_request/user_views_auto_expanding_diff_spec.rb

@@ -11,9 +11,6 @@
   let(:user) { create(:user, view_diffs_file_by_file: true) }
 
   before do
-    allow(Gitlab::Git::Diff).to receive(:size_limit).and_return(100.kilobytes)
-    allow(Gitlab::Git::Diff).to receive(:collapse_limit).and_return(10.kilobytes)
-
     project.add_developer(user)
 
     sign_in(user)